Przybylska D., Ekner-Grzyb A., Grześkowiak B. F., Grzyb T. 2019. Author correction: upconverting SrF2 nanoparticles doped with Yb3+/Ho3+, Yb3+/Er3+ and Yb3+/Tm3+ ions — optimisation of synthesis method, structural, spectroscopic and cytotoxicity studies. Scientific Reports. 9(1): 17520. doi:10.1038/s41598-019-53897-6